The long term objectives are to understand novel mechanisms of secretory protein export in Plasmodia and to elucidate how they differ from those in higher cells in order to develop them as new targets for drugs against the parasite. The specific aims are to identify and characterize the parasite's Golgi complex, its activities of protein export and are direcfly relevant to understanding the assembly and function of the Golgi in eukaryotes and how the malarial organelle targets proteins and membrane to the red cell. In the asexual blood stages Plasmodium has a complex relationship with its host which is poorly understood at both the biochemical and the structural level. The use of microscopic, biochemical and molecular biological tools to analyze cellular parasite phenomena should elucidate relevant modes of host-parasite interaction. In general, mechanisms for the regulation of secretory pathways are conserved in cells. There is evidence for a Golgi complex that regulates protein export from within the parasite. Functional similarities between plasmodial activities and those which regulate membrane transport in higher cells suggest approaches to investigate trafficking events in Plasmodium. The in vitro cultivation of Plasmodium falciparum permits these studies in human malaria. Relatively large amounts of parasites can be grown in the laboratory to generate adequate quantities of RNA, DNA and immunopurified radiolabelled proteins. cDNA, genomic or protein structure can then be investigated by chemical and enzymatic methods to determine specific aspects of primary structure or modifications thereof, which promote membrane transport in the parasite. The use of specific antibodies to localize protein components by nucroscopy and analyses of the biosynthesis and turnover of these proteins (by immunoprecipitation of the polypeptides) enables determining their true location and the pathways of transport in the cell. The project will provide a comprehensive, mechanistic study of Golgi organization and its role in protein export in Plasmodium.